Currently on L1 visa with Employer A; Employer B ready to process H1 next year

[durga]

Dear Members, I understand that this question might have been asked earlier. Not able to locate. requesting help.
Currently I am with Employer A on L1 Visa valid till 2015; My acquaintances with another Company B are ready to process H1B next Year.
(a) I am concerned if H1 application from another Firm will have any adverse impact on the current job or L1 Visa. I fear if Company A knows about H1B, I can be in difficult situation. I can be sent back immediately.
(b) I understand there are some advantages while applying for H1B while in USA. is this correct.
(b) Officially when will my Current Employer A will know about my H1B application.
(c) Does approval of COS has any impact when H1 is changed.

[raghvi]

Dear Members, I understand that this question might have been asked earlier. Not able to locate. requesting help.
Currently I am with Employer A on L1 Visa valid till 2015; My acquaintances with another Company B are ready to process H1B next Year.
(a) I am concerned if H1 application from another Firm will have any adverse impact on the current job or L1 Visa. I fear if Company A knows about H1B, I can be in difficult situation. I can be sent back immediately.
(b) I understand there are some advantages while applying for H1B while in USA. is this correct.
(b) Officially when will my Current Employer A will know about my H1B application.
(c) Does approval of COS has any impact when H1 is changed.

a. They wont know unless you tell them or Employer A tells Employer B.
b. I dont know if any specific ones but yes, if you are in US you can apply for L1 to H1 COS and if approved can move to H1 without the need to go for stamping.
c. Same as 1.
d. Dont understand your question. If COS to H1 is approved you must work with B from H1 start date.

This is my opinion not legal advice.